How long does it take garlic to kill bacteria?

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How long does it take garlic to kill bacteria?

Garlic, the humble yet mighty herb, has long been hailed for its numerous health benefits. One of its most notable properties is its ability to kill bacteria. But how long does it take for garlic to do its magic and eliminate those microbes? Does the garlic attack discriminate between bad and good bacteria? Let’s find out.

How Does Garlic Kill Bacteria?

Garlic contains antimicrobial compounds that kill bacteria, the most important of which is allicin. When fresh garlic is chopped or crushed, the alliinase enzyme is activated and produces allicin from alliin (present in intact garlic). Allicin is not only responsible for the distinctive aroma of fresh garlic but also antibacterial activity of garlic. Allicin is known to have sulfhydryl-modifying activity and is capable of inhibiting sulfhydryl enzymes in bacteria which are essential for bacterial nutrition and metabolism.

How Long Does It Take For Garlic To Kill Bacteria?

Garlic’s antimicrobial compounds begin their bacteria-killing mission as soon as they come in contact with the microbes. 

However, it may take up to two weeks for garlic to fully clear up infections, depending on factors such as the resistance of the organisms, concentration, and formulation of garlic used.

Effect Of Garlic On Bad Bacteria

  • Garlic has been shown to exhibit a wide spectrum of antibacterial activity against many possible pathogens including species of Escherichia, Salmonella, Staphylococcus, Streptococcus, Klebsiella, Proteus, Bacillus, and Clostridium. 
  • Garlic can also be effective against mycobacterial strains that cause tuberculosis. Preclinical studies have shown that allicin in garlic not only reduces the bacterial burden in the lungs of mice infected with Mycobacterium tuberculosis but also induces strong anti-tubercular immunity.
  • Moreover, studies have found that garlic extract can effectively inhibit Helicobacter pylori, a bacterium implicated in the etiology of stomach cancer and ulcers.

What About Good Bacteria? Does Garlic Affect Probiotics?

The frequent question is “Does garlic also kill good bacteria also known as probiotics?”

🧄 Garlic does not kill every bacteria on the planet

Although garlic has an antibacterial property, this does not apply to all strains of bacteria. The effect works for only strains that are susceptible to its properties. 

🧄 Garlic feeds the beneficial gut bacteria

Garlic is a rich source of fructans (prebiotics) which promote the growth of probiotics or beneficial bacteria.

🧄 Now, let’s take a look at the research findings.

  • In another study, researchers found that aqueous extract of garlic had an antimicrobial effect on bifidobacterium species.

After all of these mixed results, we can not completely rule out the possibility that beneficial bacteria might be caught in the crossfire.

But this doesn’t necessarily mean garlic can kill probiotics because 

“Several factors affect garlic’s interaction with microorganisms”. 

  1. How is the garlic prepared

In the studies, you would see that different formulations of garlic were used. For example, garlic extract does have the powerful antibacterial allicin but contains fewer fructans than raw garlic. The inulin fructans are prebiotic fibers that the good bacteria in your gut feed and thrive on. For this reason, the trials that used garlic extract showed a killing effect on probiotics. 

  1. The degree of resistance of each probiotic bacteria

Studies revealed that Bifidobacterium was the most susceptible to bactericidal action of garlic allicin, followed by B.longum and B.lactis while Lactobacillus acidophilus was not affected at all. 

  1. How much dosage you consume

The antimicrobial activity also depends on how much garlic comes into contact with the bacteria. That’s why studies indicate that the addition of certain quantities of ground garlic or fresh garlic juice that did not show antimicrobial activity for selected probiotic strains is suitable for food matrix, especially yogurt-based products.

Can You Take Garlic And Probiotics Together?

It is not that garlic and probiotics are incompatible. Kimchi (a fermented cabbage that requires garlic in its preparation) is an example of how garlic and probiotics can exist together. Probiotics like Lactobacillus acidophilus can be taken with garlic at the same time, but caution is advised when using probiotic Bifidobacteria and garlic simultaneously.

Nonetheless, my recommendation is to take the safe side and take them separately. Moreover, according to research, the survival of probiotics in the GI tract was best when given 30 minutes before a meal (that also includes drinks like garlic juice). 

The Bottom Line

It is worth mentioning that garlic can be a powerful ally in fighting pathogenic microorganisms. Although the antimicrobial compounds in garlic may threaten the survival of probiotics as well, it is greatly dependent on several factors that I have aforementioned.

Last but not least, you should always consult your healthcare provider for professional advice when it comes to supplements.

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Dr Tun Min is s GP working in NHS UK and writing articles about supplements and vitamins based on personal clinical experience and clinical research.

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